cutting a sheet of siding in half is not difficult, just need a circular saw ($50-75) at wally world, a tape measure, pencil and straigth edge, total of maybe $100. Get some 2x4's and put the 2x4's under the 1st sheet on top, use the stack of siding sheets as your saw horses, measure 2, maybe 3 times, then use the straight edge to mark you cut, and then cut it with the circular saw. can use the straight edge clamped to the sheet of siding to make sure its a good straight cut.
Lowes/Home depot will cut the stuff for you as well but the cuts may not be "exact/perfect" in terms of measuring, straight yes, but may be off a bit in measuring.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.